4 and 9 are already in rows 7 and 9
In row 8, they must occupy r8 c1 or r8 c3
This reduces your possibilities for r8 c3 from 1, 3, 4, 7 or 9 to 4 or 9
Inspection of column 3 then shows 4, 8 and 9 fill r1 c3, r2, c3 and r8, c3
None of these entries can go in r5 c3
... which leaves just 1.